The dangers of microwaving liquids

[A Nonny Moose 8,263]

A 26-year old man decided to have a cup of coffee. He took a cup of water and put it in the microwave to heat it up (something that he had done numerous times before). I am not sure how long he set the timer for, but he wanted to bring the water to a boil. When the timer shut the oven off, he removed the cup from the oven. As he looked into the cup, he noted that the! water was not boiling, but suddenly the water in the cup "blew up" into his face. The cup remained intact until he threw it out of his hand, but all the water had flown out into his face due to the build up of energy. His whole face is blistered and he has 1st and 2nd degree burns to his face which may leave scarring.

He also may have lost partial sight in his left eye. While at the hospital, the doctor who was attending to him stated that this is a fairly common occurrence and water (alone) should never be heated in a microwave oven. If water is heated in this manner, something should be placed in the cup to diffuse the energy such as a wooden stir stick, tea bag, etc., (nothing metal).

It is however a much safer choice to boil the water in a tea kettle.

General Electric's Response:

Thanks for contacting us, I will be happy to assist you. The e-mail that you received is correct. Microwaved water and other liquids do not always bubble when they reach the boiling point. They can actually get superheated and not bubble at all. The superheated liquid will bubble up out of the cup when it is moved or when something like a spoon or tea bag is put into it.

To prevent this from happening and causing injury, do not heat any liquid for more than two minutes per cup. After heating, let the cup stand in the microwave for thirty seconds! before moving it or adding anything into it.

Here is what our local science teacher had to say on the matter: "Thanks for the microwave warning. I have seen this happen before. It is caused by a phenomenon known as super heating. It can occur anytime water is heated and will particularly occur if the vessel that the water is heated in is new, or when heating a small amount of water (less than half a cup).

What happens is that the water heats faster than the vapor bubbles can form. If the cup is very new then it is unlikely to have small surface scratches inside it that provide a place for the bubbles to form. As the bubbles cannot form and release some of the heat has built up, the liquid does not boil, and the liquid continues to heat up
> well past its boiling point.

What then usually happens is that the liquid is bumped or jarred, which is just enough of a shock to cause the bubbles to rapidly form and expel the hot liquid. The rapid formation of bubbles is also why a carbonated beverage spews when opened after having b

[s.i.X 13]

I knew this would happen with distilled water, but didn't know it would happen with any water. I'm pretty sure the particles in tap water make it safe, but I use a kettle anyway.

I don't have a microwave.

[Barbarossa 51]

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  Edited September 1, 2012 by Barbarossa  

[Voar Tok 4]

There are some myths that go with this email that need to be debunked.

First, yes, super-heating water is a common occurrence, but it usually doesn't blow up on you.  It can, but usually it doesn't.

Second, this can happen in a kettle, although, the odds of that happening are pretty darn slim.

If you want to microwave liquids, a styrofoam cup is usually the best answer as the walls are rarely smooth enough.

Finally, the coffee stirrer or something else needs to be in the cup before you microwave it and not afterwards like lots of the people who have forwarded this to me have suggested.  The reason why this works is because it breaks the surface tension, so, in reality, if you wanted to, you could also prevent that from happening by putting a little dish soap into your tea before you heat it.

EDIT: I forgot.  Tap water isn't much safer than distilled water.  They're pretty much both equal opportunity explosion risks.

[octaves 4]

Oooh man, thats creepy

My step dad always uses the microwave for water, I'm not sure for how long (it says not to use it for any time longer than 2 minutes) but I'll be sure to tell him! 

[A Nonny Moose 8,263]

And notwithstanding the put some chunks in, I have had boil overs after taking soups out of the nuke.  The best trick is to let it rest, covered for about five minutes, then insert a spoon from the side.

Do not look into nuked liquids with the rest of your face.

[Meg 368]

Originally posted by: Voar Tok

EDIT: I forgot.  Tap water isn't much safer than distilled water.  They're pretty much both equal opportunity explosion risks.quote>

Wouldn't that depend on what's in the tap water?  Whether it's "hard" or "soft" water?

Fast boil-ups can happen in the stove too.   If I boil water on the stove and add in a bowlful of frozen veggies, it will flash up and half the water will wind up outside the pan.  If, instead, I throw in 2 or 3 kernels of corn, it will have a small, quick flash up and then I can add the rest safely.

[Duke87 1,070]

Most of what's dissolved in tap water is ions or polar molecules, so it doesn't really do much to prevent superheating unless it's highly concentrated, much more so than any tap water is ever going to be. It does raise the boiling point slightly, though.

Surfactants (such as soap) break surface tension since they are nonpolar, and thus cannot take part in dipole-dipole bonding, and also prevent it from happening by getting between the polar molecules, which can. As such, a surfactant will help prevent superheating. But who wants soap in their coffee? You're better off just avoiding putting water alone in the microwave.

---------------

On another note, I am somewhat disappointed. I was expecting a thread about people experimenting with putting various things in the microwave. Always tons of fun to be had there.

Not recommended that you attempt, though, unless you're willing to risk destroying your microwave.

[Voar Tok 4]

Originally posted by: SkiGeek

Originally posted by: Voar Tok

EDIT: I forgot.  Tap water isn't much safer than distilled water.  They're pretty much both equal opportunity explosion risks.quote>

Wouldn't that depend on what's in the tap water?  Whether it's "hard" or "soft" water?quote>

No, it really doesn't matter whats in the tap water.  When you have stuff dissolved in water, all you really do is increase or decrease the boiling point.  If you wanted to prevent liquid super heating, the concentration of the solute would have to be so high that you could see it floating around in there, and even if people were likely to want to drink water with black crud floating around in it (or in the case of soft water - salt) it still all depends on if the bubbles can form and make it through the surface.

[A Nonny Moose 8,263]

Actually, with water all you need is three or four glass marbles in the bottom.

[LarksTonguesInAspic 28]

Originally posted by: Duke87

On another note, I am somewhat disappointed. I was expecting a thread about people experimenting with putting various things in the microwave. Always tons of fun to be had there.

Not recommended that you attempt, though, unless you're willing to risk destroying your microwave.quote>

 

I have...eggs explode with great force, as do potatoes if there's no holes in them. 

And Pop-Tarts in a toaster will create a 6 foot pillar of flame if left in too long. 

I had too much time on my hands as a teenager.

[A Nonny Moose 8,263]

Let us not encourage destructive experiments around the house, folks.  There are some pretty young people on here who might just try some of this stuff.

[Barbarossa 51]

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  Edited September 7, 2012 by Barbarossa  

[A Nonny Moose 8,263]

Planning a potato omelette I see.  They don't nuke very well as it is hard to get the top properly set.

[LarksTonguesInAspic 28]

The microwave wasn't damaged, it was an ancient Radarange with a stainless interior.

The Pop-Tarts were an experiment outside with an extension cord and an old toaster.

I should have clarified, I would not recommend attempting these things to anyone. 

"Professional driver on closed course" LOL

[Inusion X 1]

one time i was cooking nachos in the microwave and they caught on fire!

They weren't very good...

[Skram 4]

lol they caught on fire!thats weird good thing i don"t do that!

[Hahayoudied 3]

    LOL, I remember once I put hot coco in the microwave and it was already stirred. I didn't know that you are suppose to heat the milk and then stir it with hot coco powder. I set the microwave for 5 minutes and after 2 minutes, the hot coco started to foam and the foam spilled everywhere in the microwave. I also remember when my dad undercooked my egg and I wanted the egg to be fully cooked. He told me microwave it and I said how long? He said 7 minutes and after the egg was microwaved for 3 minutes, it exploded. I had to eat a overcooked blown up egg( it tasted horrible) and my dad  had to clean up the  microwave.

[Lyhoko Leaci 770]

A few years ago my dad put a hamburger in the microwave with the wrapper that came with it, and it caught on fire. I blew the fire out before it could do any real damage, but there is still a burn mark on the inside of the microwave. (The wrapper had metal in it)

[Haljackey 17,441]

Did you know that Microwaves are banned in Russia? Interesting fact, eh? I think it has something to do with the health standards in the country.

I could never imagine living life without a microwave. Frozen dinners in the oven? Give me a break...

[Hahayoudied 3]

Maybe the ban is for the safety of its people.

[hamsterTK 93]

when I was a kid I'd play with the microwave, the coolest thing was destroying kid's meal toys in the nuke. Once I took two forks and stuck them side by side to purposely create an arc, and they melted a little nick in the glass turntable. Also once I put an unopened metal can of tomato soup....it blew up so hard it flung the door open and spewed burnt soup everywhere...stand back lol

Ahh nothing better than a little microwave mayhem

You know honestly it's not as easy as you think to really destroy a microwave, especially a modern one where the current can't run back up the magnetron. As long as you keep yourself safe, that is the more important thing.